Attachment for grinding machines



Dec. 19, 1939.

4 Sheets-Sheet 1 Filed Jan. 20, 1939 ayz Dec. 19, 1939. H. W. MILLER ATTACHMENT FOR GRINDING MACHINES Filed Jan. 20, 1939 4 Sheets-Sheet 2 jar/y Wlii 'ller H. W. MILLER ATTACHMENT FOR GRTNDING MACHINES Dec. 19, 1939.

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Dec. 19, 1939. H. W. MILLER I ATTACHMENT FOR GRINDING MACHINES 4 Sheets-Sheet 4 Filed Jan. 20, 1959 fl'arzy WAIZZZer Patented Dec. 19,, 1939 ATTACHMENT FOR FlCE GaiNDI'NG iivmc'nmes Harry W. Miller, Lancaster, Pa.

- Application January 20 3 Claims.

' My invention-relates to grinding machines and particularly to a grinding machine adapted for sharpening the straight or stationary blades of lawn mowers. More specifically, my invention is an attachment for a grinding machine of thetype disclosed in and covered by my Patent No. '1',- 916,063 granted June 27," 1933.

The grinding machine set forth in theabove mentioned patent is for grinding the curved blades 11 0 of lawn mowers; and the subject of the present application is, as above stated, an attachment for said :machine whereby the same is adapted for grinding the straight blades, therebym'akin'g a machine adaptable'for the complete sharpening of alawn mower.

The object of my invention is to provide an attachment for a grinding machine} of the class mentioned whereby the face of the blade may be presented to the grinding tool to true the same,and then the cutting edge presented to the tool to complete the sharpening. My inventionfurther consists in a device as mentioned iii'w'hich both the face and the edge of the blade may be presented to the tool at any desired angle, transversely." A further object of my invention is to providea device mentioned in which the blade mayibe presented-to the'to'ol at any desired anglelongitudinally whereby the degree ordepth of the cut may be regulated. A further object of my invention is to provide a device of the character mentioned wherein the rotary tool is held'in stationary position and the work reciprocated across the lateral face thereof. A further object of "my invention is to provide a device of simple construction which may be read- -ily and quickly attached to the grinding machine and readily'adjusted'in position for use. Other objects will appear hereinafter.

With these objects in view my invention comprises a longitudinal member or guide ways adapted to be fixed to portions of 'the'grindingmachine, a carriage slidably mounted on said member; and a work holder 'pivotally mounted on said carriage on an axissubstantially parallel to the path of travel of the carriage and located adjacent to the grinding tool. My invention further. consists in adevice as mentioned further characterized by means for moving the work holder toward orfrom the tool without chang- BS justed to fvary the angtilarposition of the -de.

ing the position of any ofJthe other parts. My

vice to regulate-theidegre'e of cut of the tool. My invention? further consists in various details of construction andtarrangementsof parts all as will be fully describedhereinafter and particula'r'ly pointed outiin the claims. I My invention wilhbemore readily understood by ref'erencezto the accompanyingdrawings forming apart ot: this Specification. and in which- =Figure 1 is a, sideelevation of a grinding machinewiththe attachment secured in position,"

Fig. 2 is a-plan view of the same,

Fig. 3 is a plan view of the attachment upon an enlarged scale, 1 together with elements of the machine upon which the same is mounted,

Fig. 4 is an elevation of the same, parts of the 15 supporting elements of the grinding machine beingbroken away and-illustrated in section,

" Fig. 5 is an'- enlarged transverse view of the same, parts of the attachment being illustrated in section, the" section being taken substantially o'n-the line 5-5 .of Fig. 3, and illustratingthe operation of 'truingthe upper face of a lawn mower blade, j

i. Fig. 6 is an enlarged detail view illustrating the action of the tool on the blade,

Fig.7 is azview similar to Fig. 5-with other parts shown in section and illustrating the operation of sharpening the edge of the blade,

Fig. 8 is an enlarged detail view illustrating the action of the tool'on the work,

Fig. 9 is a detail section on substantially the line 9-9 of Fig. 7,.and

Fig. 10 is a detail cross section of the tool holder on the' line III-l ll of Fig. 3 but illustrated on substantially the same scale as Figs. 5 and '7.

Referring now to the drawings, I indicates generally the frame of a grinding machine such as covered in my aforesaid patent, and consists of the end members 2-2 connected at the base by tie rods 3+3 and at the top by a longitudinal 40 bar 4. The" bar 4 constitutes ways'for a reciprocating carriage 5 which carries a housed motor 6 and a grinding tool 1. Also, mounted on the carriage is a gear casing 8 and a driven gear .9; connected by suitable idler gears to a gearll) meshing-with a fixed rack ll on. the frame, and by means of which the tool is reciprocated longi- ,tudinally of the machine when used for grinding the curved blades of lawn mowers. The gears 9 and III are connected by idlers l2 and I3 mounted upon a shiftable lever M, which lever engages stop members 15 at the end of each longitudinal movement and thereby alternately shifts the gears I2 and I3 into engagement with the gear 10 to reverse the. movement of the tOOl carriage 5. This is all completely disclosed in my Patent No. 1,916,063 and needs no further description herein, as the reciprocating feature is not used in conjunction with the present invention. At each end of the frame are forwardly extending arms |6 which are mounted for vertical adjustment upon vertically disposed ways I! fixed at their upper and lower ends to the top and bottom portions of the respective frame members. The arms I6 are provided with sleeves I8 through which are threaded vertical shafts l9. These threaded shafts have their lower ends mounted in the base of the frame, and the upper ends are journalled in the top thereof and are equipped with beveled gears which mesh with gears 2| on a longitudinal shaft 22. The end of the shaft 22 is provided with a hand crank 23. It is obvious that by turning the crank 23 the arms l6 may be readily adjusted vertically. After the arms are adjusted to the proper height they may be securely fixed in position at their rear ends by set screws 24 threaded through the arms of the forked end 25 of the arm. Adjustably mounted on the outer ends of the arms I6 is a slotted member 26 upon which are adjustably mounted a pair of supports 2'! for the cross bar of a lawn mower during the sharpening of the curved blades. The portion of the device above described is a brief summary of the grinding tool set forth in the aforementioned patent.

To avoid chattering when the grinder is in operation a brace member is provided for the outer ends of each arm. These each comprise a bar 28 pivotally mounted at 29 to the base of the frame and having a slot 30 extending the greater portion of its length, through which a binding screw 3| is projected and threaded into the arm I6. This member may or may not be used, and I have illustrated it in Figs. 1, 3 and 4 but have omitted it from Fig. 2 to avoid confusion.

The attachment, forming the subject of this application, comprises generally a track or guide ways, a reciprocating carriage slidably mounted thereon, a work holder on the carriage and means for attaching the track or ways to a grinding machine. The guide ways comprise an angle iron 32 consisting of a horizontal base flange 33 and a vertically disposed flange 34. The reciprocating carriages comprise a similar but inverted angle iron consisting of a vertical flange 35 in sliding engagement with the inner face of the flange 34, and a horizontal upper flange 36 which extends over the top of the flange 34 and in the opposite direction from the flange 33. To secure the sliding member to the ways a small angle iron 31 is provided having a flange 38 arranged beneath the guide member and held in position by bolts 39 having their heads countersunk in the flange 36. A longitudinal bar 40 is secured beneath the flange 36 and engages the outer upper edge of the flange 34. The upper edge of the flange 34 is thus held between the flange 35 and the bar 40. This bar 40 preferably extends the entire length of the sliding carriage but the member 31 is considerably shorter than the same, as shown clearly in Fig. 4. A bar 4| is fixed to the upper face of the flange 53 as by rivets 42 and extends substantially the length of the device.

Interposed between said bar and the flange 35 of the sliding carriage is a bearing strip 43 which is attached at its ends 44 to the ends of the bar 4|. Adjusting screws 45 are threaded through the bar 4| at intervals to press the strip 43 against the lower outer face of the flange 35 thereby holding the same in firm but sliding engagement.

This also provides means for taking up any wear of the parts.

Carried by the sliding member is the work holder 46 which consists generally in an angle iron having the substantially vertical and horizontal flanges 41 and 48 respectively, and a clamping device for holding the work therein. In using the device, the blade of the mower and the bar to which it is permanently attached, are removed from the mower and clamped in the work holder. In the drawings, A indicates the blade and B the bar. As it is sometimes desirable to grind both the upper face of the blade and its forward edge, it is necessary to be able to clamp the work to either of the flanges, and the clamping means must be so arranged as to not interfere with the tool. To this end I provide a reversible clamping device. This comprises a bar bent substantially at its center, forming legs 49 and 50 respectively, a screw 5| threaded through the leg 49, and means for attaching the leg 50 to either flange of the holder. Each flange 41 and 48 is provided with a countersunk aperture 52 to receive a bolt 53 so that the device may be selectively attached to the holder body 45. The screw 5| impinges against the bar B of the blade A, as shown in Figs. 5 and '7; said figures illustrating the two general positions of the blade for grinding, as will appear more fully hereinafter.

Means are provided for mounting the work holder on the carriage, said means being so constructed and arranged as to permit adjustment of the holder from and toward the carriage and also permit angular adjustment of the holder transversely of the path of longitudinal movement of the same. To this end, a pair of sleeves 54 are mounted transversely of the upper flange 36 of the carriage and slidably mounted therein are telescopic members 55, each terminating in a head 56 to which a. corresponding lug 5! on the work holder is pivotally connected on a longitudinal axis by pivot pins 58. These pivot pins are formed of set screws projecting through the lugs 51 and threaded into heads 56, whereby an angular adjustment (transversely) of the work holder may be readily made. Adjacent the opposite end of each sleeve 54 from the work holder is an upstanding lug 59 in which is swiveled a screw 60 threaded into the respective telescopic member 55. The lug 59 is secured to the flange 36 of the carriage and to this end is formed with a base 59' which is interposed between said flange and the respective sleeve 54 and welded or otherwise secured to each. The screw is provided with a crank 6| .or similar means for turning the screw whereby the work holder may be moved toward or from the grinding tool After the telescopic members and the work holder carried thereby have been adjusted they are held in position by a set screw 62 threaded through the sleeve 54 and impinging against the telescopic member 55. To prevent longitudinal movement of the screw 60 the same is provided with an annular groove 63 which is engaged by a bifurcated key 64 as illustrated in Figs. 7 and 9. The key is held in position by a screw 65 extending through the respective lug 59 and threaded into said key.

To secure the inner end of the guide member in fixed position, I provide a clamp for holding said end, said clamp being arranged on a bracket detachably secured to the arm l6 adjacent its inner end. 66 indicates the bracket having a base 61 secured by tap bolts 68 to the portion 25 of said arm. By this means the bracket may be readily attached to and detached from the yoke end'25 as desired; The bracket also'includes a substantially horizontal arm 69' having a seat upon which the end of the guide member 32 "rests. On the'end of said arm 69 is'carried a Lil- 26 of the machine.

clamping member for securely holding the adjacent portion of the flange 33 upon said seat. This clamp comprises abar ll having an aperture 12 adjacent one end to receive an upwardly projecting pin '13 provided on the end of the arm 69 and has a downwardly curved opposite end 14 to engage'the guide member flange 33, as shown clearly in Figs. 5 and 7. A clamping screw 15 extends through'an aperture 16 intermediate the ends of the bar H, and is threaded into the bracket arm 69 for forcing the arm'against the guide'mernber and securing it in position upon the bracket' The bracket is also recessed at 11 to accommodate the angle iron 31 of the carriage when necessary; and an upwardly extending lug 18 adjacent said recess assists in positioning the attachment on the bracket.

The opposite end of the guide ways from that attached to the bracket 66, is adjustably secured to the cross bar 26. To this end, the guide memmember is provided with a vertically extending "handle 83 by means of which the slide is manually actuated.

In using the device for sharpening the stationary blade of a lawn mower, the grinding'machine to which it is to be attached must be set to prevent reciprocation of the carriage 5 which may be done by arranging the carriage so that the gear Ill lies beyond the teeth of the rack. However, this may be accomplished in any preferred way according to the design of the machine to which the device is attached. This will hold the rotary tool 'I in fixed position. The bracket 66 is then secured to the portion of the arm I6 by means of the bolts 68. If preferred, this bracket may be left in position as it does not interfere with the operation of the grinding machine when sharpening the curved blades of the mower. The attachment is then positioned with one end resting upon the seat 70 and the stem 19 is arranged within the sleeve 80 carried by the bar 26. The clamp screw 15 is then tightened to hold the rear end of the guide member firmly on the seat ill, and after the device is levelled the set screw 82 is tightened to support the forward end in proper vertical position. This is all the operations that are necessary to attach the device to the grinding tool.

If the straight or stationary blade of the mower is in good condition and merely needs sharpening, it is placed in the work holder 46 in the position shown in Fig. 7. However, this blade is sometimes bent or the upper face adjacent the cutting edge is damaged, in which event it is necessary to grind and refinish the upper surface. If such is the case the blade is first put in the work holder as illustrated in Fig. 5 as it is desirable to true the upper face of the blade before sharpening. In facing the blade it is impossible and impractical to face the entire upper surface, so that it is necessary to grind the same at an angle to the original face, as shown in Figs. 5 and 6 stituting the pivot pins, hereinbefore described, are loosened, the work holder set at the desired angle and the pivot screws again tightened to maintain the work holder in adjusted position. A tool I having been positioned in approximate position for work on the blade, the final adjustment between the tool and blade may be made by means of the screws 60. In sharpening the blade the work is passed across the side of the rotary tool instead of across the periphery thereof.

of the drawings. To this end, the screws 58 con- After the blade is in position, the operator grasps I thehandle 83 and slides the carriageso as to carry the work across the face of the tool as shown in Fig. 5. It will be noted with reference to Fig. 2 that the attachment is arranged at -a slight angle, and the depth of the cut may be regulated by this angular adjustment which is made by a moving sleeve 80 on the bar 26. After passing the blade across the tool, should it be found that it is necessary to cut slightly deeper this may be done by moving the sleeve 80 slightly to the right or by adjusting the work holder by means of thescrews 60.

After the upper face of the blade has been properly dressed, the blade is released from the holder, the work clamp removed and placed into the position shown in Fig. 7, the blade placed in the work holder as shown in said figure and the tool and work adjusted into proper relationship in amanner similar to that above described. The edge of the blade is then ground by reciprocating the carriage across the face of the tool and the depth of the cut may be regulated in like manner as above described. Fig. 6 illustrates the cut made in dressing the upper face of the blade and Fig. 8 illustrates the cut made in sharpening the edge, the dotted lines illustrating the portions of the blade removed during the operations,'al-

though considerably exaggerated for the purpose r of illustration.

It is obvious that inusing the device with a grinding machine of the character mentioned, the arms l6 and bar 26 supporting the device may be vertically adjusted into proper position with relation to the tool by means of the screws l9 and that the grinding tool may be arranged in fixed position adjacent to the work holder. After the work is in proper adjusted position, the only operation necessary is to reciprocate the carriage on the guide so as to move the work across the face of the tool. If, on the first reciprocation it is found that the out has not been deep enough to give a perfect finish the outer end of the device may be moved slightly to the right, as above mentioned and the carriage may be again recipro cated making a deeper cut.

I claim:

1. In a grinding machine of the class described, a frame, a rotary tool and a vertically adjustable support comprising a pair of substantially horizontal arms and'a transverse bar connecting said arms, in combination with guide ways having one end secured to one of said arms and the opposite end adjustably secured to said transverse bar, a carriage slidably mounted on said ways and a work holder on said carriage, substantially as described.

2. In a grinding machine of the class described, a frame, a rotary tool and a vertically adjustable support comprising a pair of substantially horizontal arms and a transverse bar connecting said arms, in combination with guide ways having one end secured to one of said arms and the opposite end adjustably secured to said transverse bar, a carriage mounted for reciprocation on said ways in combination with a work holder comprising an angle iron consisting of substantially vertical and horizontal flanges, lugs secured to the outer face of one of said flanges, and pivotally secured to said carriage on an axis longitudinal of the same, and a Work clamp comprising a V-shaped member, means for securing one leg of said member to the outer face of either of said flanges, and a work engaging clamp screw threaded through the opposite leg of said member, substantially as described.

3. In a grinding machine of the class described, a frame, a rotary tool and a vertically adjustable support comprising a pair of substantially horizontal arms and a transverse bar connecting said arms, in combination with guide ways having one end secured to one of said arms and the opposite end adjustably secured to said transverse bar, a carriage slidably mounted on said ways and a work holder on said carriage, and means for moving the work holder laterally with relation to the carriage.

4. In a grinding machine of the class described, a frame, a rotary tool and a vertically adjustable support comprising a pair of substantially horizontal arms and a transverse bar connecting said arms, in combination with guide ways having one end secured to one of said arms and the opposite end adjustably secured to said transverse bar, a carriage mounted for reciprocation on said ways, sleeves mounted transversely of said carriage, telescopic members arranged within said sleeves, a work holder mounted on the ends of said telescopic members and means for adjusting said telescopic members to position the work holders with relation to the tool.

5. In a grinding machine of the class described, a frame, a rotary tool and a vertically adjustable support comprising a pair of substantially horizontal arms and a transverse bar connecting said arms, in combination with guide ways having one end secured to one of said arms and the opposite end adjustably secured to said transverse bar, a carriage mounted for reciprocation on said ways, sleeves mounted transversely of said carriage, telescopic members arranged within said sleeves, a work holder pivotally attached to said telescopic members on an axis longitudinal of the Work holder, and means for adjusting said telescopic members to position the work holders with relation to the tool.

6. An attachment for a grinding machine of the character mentioned comprising guide ways formed of an angle iron having a horizontal and a vertical flange, a carriage comprising a similar angle iron having a vertical flange in sliding contact with the inner face of the vertical flange of the ways and a horizontal flange extending across the upper edge thereof, a member extending beneath the angular corner of said ways and fixed to said carriage for maintaining the same on said ways, a bearing strip mounted on the inner face of the horizontal flange of the ways and engaging the lower portion of the vertical portion of the flange of the carriage, a work holder mounted on the carriage, and means for attaching the device to a grinding machine, substantially as described.

'7. In a grinding machine of the class described, a frame, a rotary tool, and a vertically adjustable support comprising a pair of substantially horizontal arms and a transverse bar connecting said arms, in combination with a bracket secured to one of said arms adjacent its inner end, guide ways having one end resting on said bracket, a clamp for securing the adjacent portion of the guide ways to said bracket, a vertical sleeve adjustably mounted on the transverse bar, a depending stem on said ways adjacent its outer end and vertically adjustable within said sleeve, a carriage slidably mounted on said ways, a work holder on said carriage, and a handle on said carriage for manipulating the same, substantially as described.

8. An attachment for grinding machines of the character mentioned comprising guide ways, a carriage slidably mounted on said ways, a pair of sleeves transversely mounted on said carriage, telescopic members arranged within said sleeves, a swiveled screw threaded in each of said telescopic members, a work holder having a pair of lugs pivotally connected to the outer ends of said telescopic members on an axis longitudinal of the carriage and work clamping means on said holder, substantially as described.

HARRY W. MILLER. 

